I finally managed to install OpenBSD on my laptop. One problem that comes up is when I close the lid and open it back, the machine doesn't respond. I have to manually restart it. Any ideas on what the problem is??

From your description, your hardware configuration is unable to resume from a suspend. To disable suspending the system upon lid close, set the sysctl machdep.lidsuspend to zero. You can either edit the sysctl.conf file or append the setting, such as: